Prestressing permits increasing the distance between pavement joints from approximately 5 meters to approximately 150 meters. The maximum stresses in the pavement cross section occur in the joint area and they determine the dimensions, bedding indexes and reinforcements. In this respect, long and short slabs differ but little. The added expense for prestressing must be recovered from the savings in the construction and maintenance of the joints. As soon as the joints are eliminated altogether, however, substantial savings are effected in the subbase, due to the reduction of the bedding index and additional noticeable savings are made in the pavement itself, due to reductions in thickness and reinforcements. It is the purpose of the invention to apply a known prestressing system, the so-called "internal" prestressing method, and to construct pavements in such a way that joints are eliminated.
The present invention applies the "internal" prestressing as described in my U.S. Pat. No. 3,516,211, to construct pavements of any desired length, without joints. These pavements are to be poured by a finisher, so that they lie on a plane subbase and have a constant thickness.
Two methods were described in my earlier applications. In method A, the invention applied the "internal" prestress in such a way that the slab constructed last was always prestressed by means of the peripheral members of the "internal" prestress tendons, thus shortening the slab. In a second step, the core members were used to further prestress and thus shorten the last slab further. Method A was the object of the application Ser. No. 712,469, now abandoned, and the German laid-open patent application DT-P 25 37 616.
In method B, the slabs were made in a first step by a finisher, a working gap was left between the slabs of the pavement for placing jacks. This working gap was closed in a second step and prestressed. This method was the object of the German laid-open patent application DT-P 26 38 457.